1. Field of the Invention
The invention relates to a method and an apparatus for bending glass plates, in which the glass plates are heated to the bending temperature in a horizontal position in a furnace including a conveyor and transferred into a bending chamber in which they are raised by a differential gas pressure against a convex bending mold positioned above the conveying plane of the glass plates, are bent into their final shape and with the aid of a shaping ring corresponding to the final glass plate shape and are transferred from the bending chamber into a following cooling station.
2. Description of the Related Art
A method of the aforementioned type is known from U.S. Pat. No. 4,682,997. In this known method the glass plates are transferred from the roller-type continuous furnace into the following bending chamber on driven conveying rollers. The glass plates are raised from the conveying rollers in the bending chamber by means of an upwardly flowing, hot gas stream and pressed against the upper bending mold.
Another method of the aforementioned type is described in U.S. Pat. No. 3,778,244. In this known method the conveying roller train also extends from the roller-type continuous furnace into the bending chamber. In this case the glass plates are raised from the conveying rollers by suction. The vacuum required for the suction process is applied along the circumferential edge of the bending mold.
In order to achieve good quality, the glass plates heated to the bending temperature within the bending chamber must initially be very accurately positioned on the conveyor, which is generally of the roller-type, i.e., brought into the correct position with respect to the bending mold before being raised from the conveying rollers by the hot gas stream or by suction, followed by pressing against the upper bending mold. This positioning process is time consuming and lengthens a bending cycle time.